The effect of sun exposure on acne prone skin

The effect of sun exposure on acne prone skin

Propionibacterium acnes (P. acnes) is a bacterium that normally inhabits human sebaceous glands and is the major cause of acne. Specific structural and metabolic properties of this bacterium make it sensitive to light, and a specific wavelength of the visible spectrum has been established to have a bactericidal (antimicrobial killing) effect on this organism.

Additionally, in small doses, infrared radiation stimulates microcirculation, which has a beneficial effect on resorption of post-acne redness and marks. Sunlight increases the production of endorphins, thereby suppressing the stress mechanisms that stimulate the appearance of acne, and accelerates cellular division in the dermis and stratum basale (basal layer of the epidermis).

All this information sounds like great news to people with acne-prone skin. And, while a little sunshine is beneficial to those with occasional breakouts, in fact, the sun is the enemy of moderate-to-severe acne: prolonged sun exposure worsens the skin appearance immensely.

Summertime mechanisms of acne aggravation

Acne is a chronic condition; any exacerbation can be triggered by both exogenous (external) and endogenous (internal) factors. The risk of new breakouts is especially high in the summer. This is primarily due to the increased exposure to solar radiation. To emphasize: we are only talking about extended sun exposure and sunbathing!

So, how can one quickly determine the acquired dose of solar radiation? The criteria are simple: if the skin has not darkened, then the dose is medicinal; suntan is the skin's response to damage by the ultraviolet rays. Prolonged UVB radiation causes direct DNA photodamage, which triggers melanin (natural skin pigment) production, and leads to skin darkening (tanning) 2-3 days following the exposure.

In addition to the tan, however, UVB radiation also causes the depletion of epidermal Langerhans cells (immune cells present in the epidermis), the thickening of the stratum corneum (the top layer of the epidermis), sebum production imbalance, and formation of free radicals. The biggest hit from excessive exposure is not just visible skin damage, but the crippling of the skin immune system: the remaining Langerhans cells are too few in number and too inefficient in function to provide the immune support they ought to.

Increasing intensity of ultraviolet radiation triggers the release of inflammatory mediators, including various pro-inflammatory cytokines. As a consequence, the balance between the rate of division and exfoliation of epidermal cells is disturbed, which aggravates the already existing hyperkeratosis (thickening of the stratum corneum), and dry skin. Elevated skin temperature leads to increased blood supply, and this contributes to further development and spread of the inflammatory process. At the same time, the sensitivity of the sebaceous gland receptors to androgen hormones increases, which leads to the excessive production of sebum.

Not only is there an increase in sebum production, but there is also a change in its chemical composition and consistency: the amount of viscous fatty acids increases, so that sebum becomes even denser and thicker. To protect itself, the skin responds with excessive keratinization of the epidermis: a mechanical obstacle preventing the release of sebum outside. This leads to a kind of sponge effect: liquid is absorbed, but not discharged. Due to the increased air temperature and humidity, a thermostatic film is formed on the surface of the skin. The end result is a very favorable environment for bacterial growth.

It is good to remember that prolonged sun exposure is not the only hazard of a summer vacation at the beach. There are also the wind and salty seawater, which dehydrate the skin, disturb its lipid mantle, and, as the result, reduce its barrier functions, including the antimicrobial ones. Dermatologists rarely remember to advise washing off salt water immediately after swimming; yet, it is as important as protecting the skin from UV rays, and should be done with the same regularity as sunblock application.

Comedogenic effect of sun exposure accumulates gradually, over a period of a month. It can be exacerbated by the use of cosmetics in the summer heat. As the result, after a short period of perceived skin improvement, the inflammatory process escalates, the blockage of sebaceous glands occurs, and acne exacerbation develops.

It is not just the sun exposure that is the culprit of worsening acne in the summer months. The other offender is the heat, which causes excessive vasodilation (expansion of blood vessels), provoking secondary inflammation. In some cases, as a result of stagnant and inflammatory processes, multiple papules and pustules appear on the skin.

Treatments and ultraviolet radiation

Sun exposure increases the risk of external acne treatments having a deleterious effect. This primarily concerns drugs that have keratolytic properties: retinoids, benzoyl peroxide, azelaic acid, salicylic acid, etc. Avoiding sun exposure is also recommended with oral/systemic treatments. In particular, tetracycline-based medication and some oral contraceptives can lead to the development of phototoxic and photoallergic reactions. Systemic treatment of acne with isotretinoin enhances the skin's sensitivity to sunlight.

Protection against sun exposure

Nobody wants to spend the summer in the shade, but many patients with acne need to do exactly that. At the very least, people with moderate-to-severe acne or seborrhea should consult a professional regarding permissible levels of sun exposure.

Patients with a large number of inflammatory acne pustules who are being treated with external or systemic therapy should avoid direct sun exposure, in general. Moreover, the use of photoprotectant (sunblock) products is recommended. Sunblock should provide the maximum amount of sun protection (SPF), and be as light and non-comedogenic as possible (i.e. emulsions or light creams), so as to not aggravate the skin condition further. Sunblock should be applied prior to going outside, and should be removed from the skin with a mild cleansing agent as soon as it is no longer required. Skin cleansing, antiseptic protection, seboregulation, and adequate moisturizing should be given increased attention. Do not apply sunblock together with topical acne treatments, as they can interfere with each other's efficacy.

Our recommendations for treating acne

Mother Nature's flora is bountiful and varied. Based on natural botanical extracts, we developed our Anti-Zits cream (day cream) and Pimples Gel (night cream), which are all-natural acne treatments made with organic plants, some of which have a natural sunscreen effect (chamomile, for example). These products protect the skin from the negative effects of the environment.

We recommend applying anti-zits cream in the morning, to cleansed skin. We do not recommend using sunblock with this cream.

Check Out Hilee's Acne Care Products!